Allosteric regulation: An allosteric inhibitor of an enzyme usually does what in cellular control loops?

Difficulty: Easy

Correct Answer: Participates in feedback regulation

Explanation:


Introduction:
Allosteric inhibitors bind to regulatory sites distinct from the active site to modulate enzyme activity. This question probes understanding of physiological roles of allosteric inhibition in metabolic pathways.


Given Data / Assumptions:

  • Allosteric site is different from the catalytic active site.
  • Binding changes enzyme conformation and activity.
  • Metabolic pathways often use feedback loops for homeostasis.


Concept / Approach:
In feedback regulation, a downstream product accumulates and binds allosterically to an upstream enzyme, decreasing its activity to prevent overproduction. This negative feedback maintains metabolic balance without denaturing the enzyme.


Step-by-Step Solution:
Identify that allosteric inhibition modulates activity reversibly via conformational shifts.Place this mechanism within pathway control: end product inhibits a rate-limiting step.Conclude its role: participation in feedback regulation.


Verification / Alternative check:
Classic examples include end-product inhibition of the first committed step in amino acid biosynthesis pathways, ensuring tight flux control.


Why Other Options Are Wrong:
Denatures the enzyme: denaturation is a non-specific, often irreversible structural collapse, not typical allosteric regulation.

Is a hydrophobic compound: chemical polarity is irrelevant; many allosteric effectors are diverse metabolites.

Causes the enzyme to work faster: inhibitors decrease activity; activators increase it.


Common Pitfalls:

  • Confusing allosteric inhibition with irreversible inactivation.
  • Assuming allosteric ligands must be hydrophobic or share structural motifs.


Final Answer:
Participates in feedback regulation

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